Pharmaceutical composition comprising 3-beta-hydroxy-5-alpha-pregnan-20-one with improved storage and solubility properties

ABSTRACT

It is provided a pharmaceutical composition comprising 3-beta-hydroxy-5-alpha-pregnan-20-one, at least one sterol or an ester thereof and a mixture of acylglycerols with a solid fat content of less than 25% at 25° C. and 0% at 37° C. In addition it is provided a method for preparing the pharmaceutical composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser. No. 13/522,081, filed on Jul. 13, 2012, which is a national phase under 35 U.S.C. §371 of PCT International Application No. PCT/SE2011/050036 which has an International Filing Date of Jan. 14, 2011, which claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 61/295,027, filed Jan. 14, 2010 and Swedish Patent Application No. 1050029-6 filed on Jan. 14, 2010. The contents of each application recited above are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates generally to an improved formulation of 3-beta-hydroxy-5-alpha-pregnan-20-one.

BACKGROUND ART

3-beta-hydroxy-5-alpha-pregnan-20-one is a steroid in the pregnane family and a modulator of GABA_(A)-receptor activity which is indicated for the treatment of sex/stress steroid induced disorders conditions (WO99/45931). 3-beta-hydroxy-5-alpha-pregnan-20-one is poorly soluble in many therapeutically acceptable solvents, which makes it difficult to administer the compound to a patient.

In animal studies, 3-beta-hydroxy-5-alpha-pregnan-20-one has been intravenously administered to rats in a formulation containing cyclodextrin (WO99/45931).

Grant et al (JPET 326:354-362, 2008) has administered 3-beta-hydroxy-5-alpha-pregnan-20-one to monkeys by using a formulation with hydroxypropyl β-cyclodextrin.

Formulations with cyclodextrins are not suitable for administration to human patients. One reason for this is, because 3-beta-hydroxy-5-alpha-pregnan-20-one is poorly soluble, the formulation results in a large therapeutic volume that can only be administered intravenously.

Since 3-beta-hydroxy-5-alpha-pregnan-20-one is poorly soluble in water there is still no pharmaceutically acceptable formulation for this compound.

DEFINITIONS

As used in the present application, the following terms have the specified meanings unless otherwise specified.

By “acylglycerol” is meant all types and combinations of fatty acids esterified to glycerol.

By “medium-chain acylglycerol” is meant a mixture of acylglycerols where the total combined percentage of octanoic (caprylic) acid and decanoic (capric) acid is at least 95%.

By “solid fat content” is meant the percentage of solid as determined by pulse NMR (nuclear magnetic resonance).

“Room temperature” denotes a temperature of between 18° C. and 25° C.

“UC1010” denotes 3-beta-hydroxy-5-alpha-pregnan-20-one.

“Sterol or ester thereof” denotes steroids with at least one hydroxyl group and esters of said steroids where at least one hydroxyl group has been used for the synthesis of an ester.

Steroids, such as sterols, are usually described by the number of carbon atoms in the compound. Thus, for example, cholesterol is a C27 sterol, which indicates that the compound consists of 27 carbon atoms.

Unless stated otherwise, concentrations are stated as mg/g, that is, mg per gram of pharmaceutical composition.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 shows mean plasma concentrations of 3-beta-hydroxy-5-alpha-pregnan-20-one (ng/mL) in rabbits following subcutaneous administration of 3-beta-hydroxy-5-alpha-pregnan-20-one in sesame oil with cholesterol (1:1) in two doses: 1 mg/kg (squares) and 5 mg/kg (circles).

FIG. 2 shows 3-beta-hydroxy-5-alpha-pregnan-20-one concentration in filtrate (0.2 μm) from a suspension of 3-beta-hydroxy-5-alpha-pregnan-20-one in relation to cholesterol:3-beta-hydroxy-5-alpha-pregnan-20-one ratio.

FIGS. 3a, 3b, 4a and 4b show photographs of suspensions of 3-beta-hydroxy-5-alpha-pregnan-20-one.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved formulation of 3-beta-hydroxy-5-alpha-pregnan-20-one in a pharmaceutically acceptable carrier.

Another object of the present invention is to provide a formulation of 3-beta-hydroxy-5-alpha-pregnan-20-one with enhanced storage properties.

Yet another object is to provide a formulation of 3-beta-hydroxy-5-alpha-pregnan-20-one with improved pharmacokinetics.

Yet another object of the present invention is to provide a formulation of 3-beta-hydroxy-5-alpha-pregnan-20-one with increased solubility in a pharmacologically acceptable carrier.

These and other objects are met by a first general aspect of the present invention which provides a pharmaceutical formulation comprising 3-beta-hydroxy-5-alpha-pregnan-20-one, at least one sterol or an ester thereof and a mixture of acylglycerols with a solid fat content of less than about 25% at 25° C. and about 0% at 37° C.

In a second general aspect of the present invention there is provided methods for preparing a pharmaceutical composition.

In a third general aspect of the present invention there is provided a pharmaceutical composition obtainable according to a method according to the invention.

In a fourth general aspect of the present invention there is provided use of a pharmaceutical composition for the treatment of conditions of the central nervous system.

DETAILED DESCRIPTION

The inventors have found that the addition of a sterol surprisingly increases the solubility and improves the pharmacokinetics of 3-beta-hydroxy-5-alpha-pregnan-20-one in acylglycerols.

Generally, the pharmaceutical composition comprises 3-beta-hydroxy-5-alpha-pregnan-20-one, at least one sterol or an ester thereof and a mixture of acylglycerols with a solid fat content of less than about 25% at 25° C. and about 0% at 37° C.

In particular a sterol with a hydroxyl group bound to the third carbon atom of the sterol structure is useful in the invention. The sterol may be cholesterol or beta-sitosterol, but also other sterols such as stigmasterol, brassicasterol or avenasterol may be used. In particular, cholesterol may be used.

In addition, cholesteryl esters can be used. Examples of such esters are sodium cholesteryl sulphate, cholesteryl bensoate, cholesteryl acetate, cholesteryl caprylate, cholesteryl decanoate, cholestyl palmitate, cholesteryl oleate and cholesteryl stearate.

The sterol or ester thereof can be a C18-C30 sterol or an ester thereof, a C21-C27 sterol or an ester thereof, or a C27-C29 sterol or ester thereof.

The pharmaceutical composition can, in a first embodiment, be such that 3-beta-hydroxy-5-alpha-pregnan-20-one is essentially dissolved in the composition. Thus 3-beta-hydroxy-5-alpha-pregnan-20-one can be dissolved or essentially dissolved according to this embodiment of the invention.

The weight ratio of sterol (or ester thereof) to 3-beta-hydroxy-5-alpha-pregnan-20-one can, in this embodiment, be in the range of about 1:10 to 10:1. The sterol or ester thereof may be added in an amount that is similar to the amount of 3-beta-hydroxy-5-alpha-pregnan-20-one by weight. Because 3-beta-hydroxy-5-alpha-pregnan-20-one and a sterol have similar molecular weights this results in almost equimolar amounts of 3-beta-hydroxy-5-alpha-pregnan-20-one to sterol.

Thus, the weight ratio of sterol to 3-beta-hydroxy-5-alpha-pregnan-20-one can be in the range of from 1:5 to 5:1. In particular, the weight ratio of sterol to 3-beta-hydroxy-5-alpha pregnan-20-one can be from 1:3 to 3:1.

Suitable concentrations of 3-beta-hydroxy-5-alpha pregnan-20-one are between 0.1 mg/g and 75 mg/g. The concentration of 3-beta-hydroxy-5-alpha pregnan-20-one can also be between 1 mg/g and 50 mg/g, between 5 mg/g and 30 mg/g or between 10 mg/g and 25 mg/g.

Alternatively, in a second embodiment, the pharmaceutical composition comprises a suspension of 3-beta-hydroxy-5-alpha-pregnan-20-one. In this case the pharmaceutical composition will comprise 3-beta-hydroxy-5-alpha-pregnan-20-one in particles as well as 3-beta-hydroxy-5-alpha-pregnan-20-one dissolved in the composition. The sterol increases the soluble fraction of 3-beta-hydroxy-5-alpha-pregnan-20-one in such a suspension compared to a suspension without a sterol. One advantage with a suspension is that the formulation can contain a high concentration of 3-beta-hydroxy-5-alpha-pregnan-20-one. An additional advantage with a composition that comprises a suspension is that it results in slow release of 3-beta-hydroxy-5-alpha-pregnan-20-one.

When the pharmaceutical composition comprises a suspension, the particles are preferably of a range of sizes that is not engulfed by macrophages. Macrophages do primarily engulf particles of a size that is 2-3 micrometer (Champion et al, Pharm Res 2008; 25(8):1815-1821).

In this second embodiment, the weight ratio of sterol (or ester thereof) to 3-beta-hydroxy-5-alpha pregnan-20-one can be in the range of about 1:10 to 10:1. The weight ratio of sterol to 3-beta-hydroxy-5alpha pregnan-20-one can be in the range of from 1:5 to 5:1. In particular, the weight ratio of sterol to 3-beta-hydroxy-5-alpha-pregnan-20-one can be from 1:4 to 3:1 or from 1:3 to 3:1.

Suitable concentrations of 3-beta-hydroxy-5-alpha-pregnan-20-one are, in this second embodiment, between 0.1 mg/g and 750 mg/g. The concentration of 3-beta-hydroxy-5-alpha-pregnan-20-one can also be between 1 mg/g and 300 mg/g, between 1 mg/g and 100 mg/g, between 1 mg/g and 50 mg/g, between 5 mg/g and 30 mg/g or between 10 mg/g and 25 mg/g.

The following applies to the invention in general.

Generally, the mixture of acylglycerols is characterized in that it has a solid fat content of less than about 25% at 25° C. and about 0% at 37° C. Thus, the solid fat content is, for practical purposes, 0% at 37° C. The solid fat content is at most 0.01% at 37° C.

The mixture of acylglycerols can be a vegetable oil. Thus, it can be a vegetable oil selected from the group consisting of sesame oil, peanut oil, olive oil, and castor oil, or mixtures thereof.

In particular the mixture of acylglycerols can be a medium-chain acylglycerol, that is, a mixture of acylglycerols wherein the total combined percentage of fatty acids with 8 carbon atoms (octanoic acid) and 10 carbon atoms (decanoic acid) is at least 95%. The medium-chain acylglycerol can be various mixtures of monoacylglycerols, diacylglycerols and triacylglycerols.

The medium-chain acylglycerol can consist of from about 50% to about 65% of monoacylglycerols, about 25% to about 35% of diacylglycerols, less than about 5% of triacylglycerols and less than about 2.5% of glycerol. An example of such a medium chain acylglycerol is Akoline MCM.

The medium-chain acylglycerol can be such that it comprises at least about 95% triacylglycerols. Akomed R MCT is an example of such a medium-chain acylglycerol.

The mixture of acylglycerols can comprise a mixture of a vegetable oil and a medium-chain acylglycerol. The mixture of acylglycerols can comprises a mixture of castor oil and a medium-chain acylglycerol where castor oil is present in an amount of between 40% and 60% by weight. The mixture of acylglycerols can consist of about 48% by weight of castor oil and about 52% by weight of a medium-chain acylglycerol. In particular the mixture of acylglycerols can consist of about 48% by weight castor oil and about 52% by weight of a medium-chain acylglycerol.

The pharmaceutical composition may comprise additional excipients known to a person skilled in the art such as antioxidants, preservatives, surfactants, coloring, flavoring, or thickening agents.

The pharmaceutical composition can be administered to the patient by different means. Thus, it may be administered orally, parenterally or topically. Thus, the pharmacological composition may be administered subcutaneously, intramuscularly, intravenously, nasally, transdermally or vaginally.

In a second general aspect of the present invention there is provided methods for preparing a pharmaceutical composition of 3-beta-hydroxy-5-alpha-pregnan-20-one.

One method, in which 3-beta-hydroxy-5-alpha-pregnan-20-one is dissolved or essentially dissolved in the composition, comprises the steps of a) dissolving 3-beta-hydroxy-5-alpha-pregnan-20-one in ethanol, b) adding a mixture of acylglycerols with a solid fat content of less than about 25% at 25° C. and about 0% at 37° C. and a sterol or ester thereof, c) mixing until a homogeneous liquid is obtained and d) evaporating the ethanol.

When the mixture of acylglycerol is a solid or a semi-solid at room temperature, such as a medium-chain acylglycerol, the method may comprise a further step, which is the melting of the medium-chain acylglycerol before mixing it with the ethanol-drug preparation. The melting step enables the homogeneous mixing of this type of acylglycerol with other components. Once melted and mixed with the other components, the preparation remains in a liquid state for at least the time periods indicated in Table 1.

When the formulation comprises a suspension, the formulation is advantageously prepared according to a method that comprises the following steps: 1) dissolving or suspending the sterol or ester thereof in the mixture of acylglycerols, 2) suspending 3-beta-hydroxy-5-alpha-pregnan-20-one in the acylglycerol-sterol mixture, 3) gently mixing. Surprisingly, this procedure leads to suspended particles comprising 3-beta-hydroxy-5-alpha-pregnan-20-one of smaller size.

In a third general aspect of the present invention there is provided pharmaceutical compositions obtainable by the methods according to the second aspect of the invention.

In a fourth general aspect of the present invention there is provided the use of the pharmaceutical composition according to the invention for the treatment or prevention of conditions of the central nervous system.

The pharmaceutical composition can be used to treat or prevent conditions of the central nervous system. Examples of such conditions that can be treated are epilepsy, menstruation cycle dependant epilepsy, depression, stress related depression, migraine, tiredness and in particular stress related tiredness, premenstrual syndrome, premenstrual dysphoric disorder, menstrual cycle linked mood changes, stress related memory changes, menstrual cycle linked memory changes, Alzheimer's dementia, menstrual cycle linked difficulties in concentration, menstrual cycle linked sleep disorders and tiredness, substance abuse, menstrual cycle linked alcoholism, or combinations thereof.

In particular the pharmaceutical composition can be used to treat steroid induced mood disorders, in particular premenstrual dysphoric disorder.

The pharmaceutical composition can also be used for treating or preventing side effects of oral contraceptives and postmenopausal therapy.

The pharmaceutical composition can also be used for control or termination of steroid-induced anesthesia.

EXAMPLES

The invention will now be described with non-limiting examples.

In order to find a pharmaceutical composition comprising 3-beta-hydroxy-5-alpha-pregnan-20-one, several different vehicles and combinations of vehicles were evaluated. 3-beta-hydroxy-5-alpha-pregnan-20-one was dissolved in various vehicles and was evaluated by eye for physical stability at room temperature over time. A formulation that did not undergo any visible changes in appearance and remained clear on storage in room temperature without signs of haziness, precipitation, sedimentation, phase separation into two or more liquid phases or change of colour, within 30 days was considered as “stable”.

In addition, the particle size and solubility of 3-beta-hydroxy-5-alpha-pregnan-20-one in formulations comprising a suspension of 3-beta-hydroxy-5-alpha-pregnan-20-one were evaluated.

General Procedure for Examples 1-49

The following procedure was adopted for the preparation of 3-beta-hydroxy-5-alpha-pregnan-20-one-containing formulations.

The desired amount of 3-beta-hydroxy-5-alpha-pregnan-20-one and sterol (for example cholesterol) was weighed in a 100 ml or 250 ml round-bottomed flask. To every gram of the mixture of 3-beta-hydroxy-5-alpha-pregnan-20-one and sterol a volume of about 30 ml of absolute ethanol was added. The mixture was treated in an ultrasonication bath (not exceeding 50° C.) until a clear liquid was obtained. This was normally accomplished within 10 minutes. The additional lipid ingredients indicated in the “Vehicle” column in Table 1 was then added up to 20 g. The resulting mixture was gently shaken by hand until a clear, homogeneous liquid was obtained. When the lipid was a solid at room temperature it was melted in the warm ultrasonication bath to a liquid form before addition.

Compounds from the following suppliers were used (product numbers within brackets): Cholesterol from Sigma (C8503), olive oil and peanut oil from Apoteket, Sweden (26 36 16 and 26 66 01, respectively), sesame oil from Fluka (85067), and castor oil from Sigma (259853). Akomed R medium-chain triacylglycerol (MCT) and Akoline medium-chain monoacylglycerol (MCM) were both from AarhusKarlshamns Sweden AB, Karlshamn, Sweden.

The alcohol was evaporated from the liquid on a rotary evaporator at a pressure of about 25 mbar and a temperature of about 40° C. until the weight of the flask was essentially constant. The remaining ethanol content was essentially less than 1%. The aim was to obtain a liquid with the appearance of clear oil at room temperature. The oily liquid was then transferred to clear glass vials and stored at room temperature until evaluation.

The samples were evaluated by observing the samples in the glass vials and recording signs of haziness, precipitation, sedimentation, phase separation into two or more liquid phases, or change of colour after 1 or 2 days after preparation and after 30 days after preparation. In some cases, other time intervals were used (indicated in Table 1). Where indicated, the entire sample was placed in a refrigerator (2-8° C.) to provoke precipitation.

Example 1

3-beta-hydroxy-5-alpha-pregnan-20-one (UC1010) (5 mg/g) and peanut oil was mixed into an emulsion with ethanol as described above in the concentrations shown in Table 1, and the ethanol was evaporated. The final weight of the preparation was 20 g. The mixture then had the form of an oily liquid. After one day when the sample was evaluated there were signs of precipitation. At 30 days the precipitate has formed a bottom sediment. Thus, the formulation was not stable.

Example 2

Example 2 was carried out essentially as Example 1 with the difference that cholesterol (5.5 mg/g) was added. When the sample was evaluated after one day the appearance of the sample had not changed. It was still unchanged after 30 days and after four months. After five months there was a slight precipitation. Example 2 compared with Example 1 shows how the addition of 5.5 mg/g cholesterol to a solution of 5 mg/g 3-beta-hydroxy-5-alpha-pregnan-20-one in peanut oil substantially increases the solubility so that, instead of precipitating, no precipitation occurred and the sample was stable for four months. However, a slight sedimentation occurred after 5 months.

Examples 3 to 49

Examples 3 to 49 were carried out essentially as described above with the variations with regard to 3-beta-hydroxy-5-alpha-pregnan-20-one concentration, acylglycerol mixture used, sterol used and sterol concentration that are shown in Table 1.

The data from examples 1 to 49 is presented in Table 1. The effect of addition of cholesterol is, for example, evident in examples 8 and 12, where the addition of cholesterol (10 mg/g) substantially increased solubility so that the sample did not precipitate but instead was stable for 12 months.

In Table 1, “Weighed amount of UC1010 (mg/g)” is the amount of 3-beta-hydroxy-5-alpha-pregnan-20-one per gram of final total composition including sterol (when a sterol is present). “Vehicle” denotes the carrier being tested. The amount of sterol is stated as “mg/g”, that is, the weight of sterol per weight of final total composition, including 3-beta-hydroxy-5-alpha-pregnan-20-one. “Appearance at preparation” describes the change of appearance of the mixture during preparation; usually the preparation is initially an emulsion or a solution whereas it has an oily appearance after evaporation of the ethanol; “Unchanged” denotes a sample that was stable and where thus 3-beta-hydroxy-5-alpha-pregnan-20-one remained in solution, without visible signs of haziness, precipitation, sedimentation, phase separation into two or more liquid phases or change of colour. This is also indicated by an asterisk (*) in the table.

TABLE 1 Weighed Appearance after Appearance after amount of 1-2 days or other 30 days or other Batch UC1010 Appearance at time period that time period that is Example name (mg/g) Vehicle preparation is indicated indicated Comments 1 ACA09 5 Peanut oil Emulsion to oil Signs of Bottom sediment 0630-1 precipitation 2 ACA09 5 Peanut oil + Emulsion to oil Unchanged * Slight sedimentation 0629-6 cholesterol (5.5 mg/g) after 5 months 3 ACA09 10 Peanut oil Emulsion to Precipitation in 0629-4 suspension almost the entire sample volume 4 ACA09 10 Peanut oil + Emulsion to oil Bottom sediment 0629-3 cholesterol (10 mg/g) (precipitation after a few hours) 5 ACA09 20 Peanut oil + Emulsion to oil Bottom sediment 0629-5 cholesterol (20 mg/g) (precipitation after a few hours) 6 ACA09 10 Olive oil + Emulsion to oil Bottom sediment 0629-8 cholesterol (10 mg/g) 7 ACA09 3 Sesame oil + Emulsion to oil Unchanged * Slight sedimentation 0709-2 cholesterol (3 mg/g) after 13 months 8 ACA09 5 Sesame oil Emulsion to oil Precipitation Bottom sediment 0702-2 9 ACA09 5 Sesame oil + Emulsion to oil Unchanged * Precipitation of 0822-B cholesterol (2.5 mg/g) crystals after 2 months 10 ACA09 5 Sesame oil + Emulsion to oil Unchanged * A few particles on the 0702-1 cholesterol (5 mg/g) bottom 11 ACA09 5 Sesame oil + Emulsion to oil Unchanged * Precipitation of 0822-A cholesterol (5 mg/g) crystals after 2 months 12 ACA09 5 Sesame oil + Emulsion to oil Unchanged * Unchanged after 12 0822-C cholesterol (10 mg/g) months * 13 ACA09 10 Sesame oil + Emulsion to oil Precipitation of 0822-E cholesterol (5 mg/g) crystals 14 ACA09 10 Sesame oil + Emulsion to oil Precipitation of 0822-D cholesterol (10 mg/g) crystals 15 ACA09 11 Sesame oil + Emulsion to oil Precipitation of 0822-F cholesterol (20 mg/g) crystals 16 ACA09 10 Sesame oil + Emulsion to oil Unchanged * Crystals on the 0716-7 β-sitosterol (10 mg/g) bottom an on the walls of the vial 17 ACA09 10 Akomed R MCT Solution to oil Precipitation of 1024-1 crystals within an hour 18 ACA09 10 Akomed R MCT + Solution to oil Slight precipitation 1024-2 cholesterol (10 mg/g) of crystals on the bottom after 2 days 19 ACA09 15 Akomed R MCT + Solution to oil Slight precipitation 1025-1 cholesterol (15 mg/g) of crystals on the bottom after 24 hours 20 ACA09 10 50% Akomed R Solution to oil Unchanged * Unchanged after 10 1024-3 MCT, 50% Akoline months * MCM 21 ACA09 10 50% Akomed R Solution to oil Unchanged * Unchanged after 10 1024-4 MCT, 50% Akoline months * MCM + cholesterol (10 mg/g) 22 ACA09 15 50% Akomed R Solution to oil Slight precipitation 1025-2 MCT, 50% Akoline of crystals on the MCM bottom after 1 week 23 ACA09 15 50% Akomed R Solution to oil Unchanged * Unchanged after 10 1025-3 MCT, 50% Akoline months * MCM + cholesterol (15 mg/g) 24 ACA09 20 50% Akomed R Solution to oil Slight precipitation 1026-1 MCT, 50% Akoline of crystals on the MCM bottom after 24 hours 25 ACA09 20 50% Akomed R Solution to oil Unchanged * Very slight 1026-2 MCT, 50% Akoline precipitation after MCM + 2.5 months cholesterol (20 mg/g) 26 ACA09 25 50% Akomed R Solution to oil Slight precipitation 1101-1 MCT, 50% Akoline of crystals on the MCM + bottom after 3 cholesterol (25 mg/g) days 27 ACA09 30 50% Akomed R Solution to oil First sign of 1102-1 MCT, 50% Akoline precipitation after MCM + 2 days cholesterol (30 mg/g) 28 ACA09 15 Castor oil Solution to oil Slight precipitation 1025-4 of crystals on the bottom after 26 days 29 ACA09 20 Castor oil Solution to oil Slight precipitation 1026-3 of crystals on the bottom after 3 days 30 ACA09 20 Castor oil + Solution to oil Unchanged * Unchanged after 10 1101-2 cholesterol (20 mg/g) months * 31 ACA09 25 Castor oil + Solution to oil Unchanged * Unchanged after 1 Unchanged 1109-1 cholesterol (25 mg/g) month, very slight after 1 week precipitation after 2 refrigerated * months 32 ACA09 30 Castor oil + Solution to oil Slight precipitation Small crystals 1109-2 cholesterol (31 mg/g) of crystals on the on the bottom after 8 bottom after days 1 week refrigerated - unchanged after 2 days * 33 ACA09 40 Akoline MCM Solution to oil Massive 1122-1 precipitation within an hour 34 ACA09 40 Akoline MCM + Solution to oil Unchanged after Precipitation after 1 1122-2 cholesterol (40 mg/g) 24 hours * week 35 ACA09 25 50% Castor oil, 50% Solution to oil Unchanged * Unchanged after 10 After 1 week 1101-4 Akoline MCM + months * refrigerated, cholesterol (25 mg/g) the entire sample was solidified, Slight precipitation after melting 36 ACA09 30 50% Castor oil, 50% Solution to oil Unchanged * Unchanged after 1 After 1 week 1102-2 Akoline MCM + month, very slight refrigerated, cholesterol (30 mg/g) precipitation after the entire approx 2 months sample was solidified, Slight precipitation after melting 37 ACA09 34 48% Castor oil, 52% Solution to oil Unchanged after Precipitation in entire Unchanged * 1108-1 Akoline MCM + 15 days * sample after 1 month after 1 week cholesterol (34 mg/g) refrigerated 38 ACA09 38 50% Castor oil, 50% Solution to oil Slight precipitation Small crystals 1108-2 Akoline MCM + of crystals on the on the cholesterol (38 mg/g) bottom after 9 bottom after days 1 week refrigerated - unchanged after 2 days 39 ACA09 40 50% Castor oil, 50% Solution to oil Massive 1120-3 Akoline MCM + precipitation after cholesterol (20 mg/g) 24 hours 40 ACA09 40 50% Castor oil, 50% Solution to oil Massive 1120-1 Akoline MCM + precipitation after cholesterol (40 mg/g) 24 hours 41 ACA09 40 47.3% Castor oil, Solution to oil Unchanged after Starts to precipitate 1122-3 47.3% Akoline 24 hours * MCM, 5.4% benzyl alcohol + cholesterol (40 mg/g) 42 ACA09 40 50% Castor oil, 50% Solution to oil Very slight 1120-2 Akoline MCM + precipitation of cholesterol (60 mg/g) crystal sin the entire sample after 24 h 43 ACA09 45 45% Castor oil, 55% Solution to oil Slight precipitation Crystals on 1108-3 Akoline MCM + of crystals on the the bottom cholesterol (45 mg/g) bottom after 9 after 1 week days refrigerated 44 ACA09 45 50% Castor oil, 50% Solution to oil Slight precipitation 1121-1 Akoline MCM + of crystal sin the cholesterol (67.5 mg/g) entire sample after 24 h 45 ACA09 50 50% Castor oil, 50% Solution to oil Very slight 1121-2 Akoline MCM + precipitations of cholesterol (75 mg/g) crystal sin the entire sample after 24 h 46 ACA09 5 Olive oil Emulsion to oil Unchanged after Crystals at the bottom 1216-2 4 days, first signs after 9 months of precipitation after 5 days 47 ACA09 5 Olive oil + Emulsion to oil Unchanged after Unchanged after 8 1216-1 cholesterol (10 mg/g) 3 weeks * months 48 ACA09 7.5 Olive oil Emulsion to oil Precipitation after 1221-2 approx. 1 hour 49 ACA09 7.5 Olive oil + Emulsion to oil Unchanged after Crystals at the bottom 1221-1 cholesterol (7.5 mg/g) 1 day, very slight after 8 months precipitation after 1 week

Examples 50-75

Examples 50 to 75 were carried out essentially as examples 1-49. Akoline Medium-Chain Monoglyceride (MCM) (Batch 8192270 and 8218940) and Akomed R Medium-Chain Triglyceride (MCT) (Batch 4765) were obtained from AarhusKarlshamns Sweden AB, Karlshamn, Sweden. Absolute ethanol (>99%) was obtained from VWR International.

The procedure for making and evaluating lipid-based formulations was as follows: The batch sizes were either 20 g or 100 g of final formulation. The desired amounts of 3-beta-hydroxy-5-alpha-pregnan-20-one and cholesterol were weighed in a round-bottomed flask, 250 or 1000 ml depending on the batch size.

To every gram of 3-beta-hydroxy-5-alpha-pregnan-20-one and cholesterol mixture a volume of about 15 to 30 ml of absolute ethanol was added. The smaller volume of alcohol per gram of solute was used when preparing the largest batch size of 100 g of final formulation. The mixture was treated in an ultrasonication bath (not exceeding 55° C.) until a clear solution was obtained. This was normally accomplished within a few minutes. The glycerides were then added and the resulting mixture was treated in the ultrasonication bath for a few seconds until a clear, homogeneous liquid was obtained. The alcohol was evaporated from the liquid on a rotary evaporator at a pressure of about 20 mbar and a temperature of about 40° C. until weight of the flask was more or less constant. Normally, the remaining ethanol content was 0.5% (w/w) or less. The evaporation time was 0.5-1.5 h, depending on the batch size. The aim was to obtain a practically uncolored liquid with the appearance of a clear oil at room temperature. The liquid was transferred to clear glass vials, which were stored at room temperature until evaluation. Some selected formulations were portioned and stored at 2-8° C. for limited period of time.

The evaluation comprised observation of the physical stability at room temperature over time. The samples were observed for haziness, precipitation of particles, aggregates or crystals, and subsequent sedimentation and/or phase separation into two or more liquid phases, and/or change of colour.

It was possible to dissolve up to 25 mg of 3-beta-hydroxy-5-alpha-pregnan-20-one per gram of final formulation based on 50% MCT and 50% MCM (examples 68 and 69) without any noticeable change in appearance when stored at room temperature for more than 1 month. One of the samples (example 69) also withstood storage at 2-8° C. and repeated temperature cycling.

In order to check the robustness and reproducibility of the formulations and the procedure for the preparation thereof, a scaling up of the batch size from 20 g to 100 g of final formulation was performed. The compositions corresponding to examples 60 and 69 were selected for this procedure. From the behavior during preparation and the initial observations of the resulting formulations (examples 74 and 75) it can be concluded that the adopted procedure is both robust and reproducible for making up to 100 g of formulation.

TABLE 2 Amount Appearance after of Appearance after 1-2 about 1 month (if not Batch UC1010 Appearance at days at room otherwise stated) at Example name (mg/g) Vehicle preparation temperature room temperature Comments 50 ACA10 30 50% Akoline Solution to oil Signs of precipitation Precipitation 0129-1 MCM, 50% after 1 day Akomed R MCT + cholesterol (30 mg/g) 51 ACA10 30 50% Akoline Solution to oil Signs of precipitation Precipitation 0129-2 MCM, 50% after 1 day Akomed R MCT + cholesterol (45 mg/g) 52 ACA10 28 50% Akoline Solution to oil Unchanged Precipitation Signs of 0129-3 MCM, 50% precipitation Akomed R after 1 day in MCT + the cholesterol refrigerator, (56 mg/g) substantial precipitation after 2 days 53 ACA10 30 67% Akoline Solution to oil Signs of slight Precipitation 0130-1 MCM, 33% precipitation after 2 days Akomed R MCT + cholesterol (30 mg/g) 54 ACA10 30 67% Akoline Solution to oil Unchanged Precipitation 0130-2 MCM, 33% Akomed R MCT + cholesterol (45 mg/g) 55 ACA10 30 67% Akoline Solution to oil Unchanged Precipitation 0130-3 MCM, 33% Akomed R MCT + cholesterol (60 mg/g) 56 ACA10 20 50% Akoline Solution to oil Unchanged Unchanged after 29 Withstand 3 0203-B MCM, 50% weeks days in the Akomed R refrigerator, MCT + but not 4 days, cholesterol due to (40 mg/g) solidification of MCM 57 ACA10 20 50% Akoline Solution to oil Unchanged Unchanged after 29 Withstand 3 0203-C MCM, 50% weeks weeks in the Akomed R refrigerator MCT + cholesterol (60 mg/g) 58 ACA10 20 50% Akoline Solution to oil First signs of Precipitation 0204-1 MCM, 50% precipitation after a few Akomed R hours, large star-shaped MCT + crystals after 2 days cholesterol (100 mg/g) 59 ACA10 20 30% Akoline Solution to oil Unchanged after 3 days Precipitation 0204-2 MCM, 70% Akomed R MCT + cholesterol (40 mg/g) 60 ACA10 20 30% Akoline Solution to oil Unchanged Unchanged after 7 Withstand 6 0206-1 MCM, 70% weeks days in the Akomed R refrigerator, MCT + but had cholesterol precipitated (60 mg/g) after about 2 weeks without concomitant solidification of MCM Massive precipitation after 28 weeks 61 ACA10 20 30% Akoline Solution to oil First signs of Precipitation 0206-2 MCM, 70% precipitation after about Akomed R 30 min MCT + cholesterol (100 mg/g) 62 ACA10 20 15% Akoline Solution to oil Precipitation Precipitation 0206-3 MCM, 85% Akomed R MCT + cholesterol (40 mg/g) 63 ACA10 20 15% Akoline Solution to oil Unchanged after 1 days Precipitation 0206-4 MCM, 85% Akomed R MCT + cholesterol (60 mg/g) 64 ACA10 20 15% Akoline Solution to oil Signs of precipitation Precipitation 0206-5 MCM, 85% directly after evaporation Akomed R MCT + cholesterol (100 mg/g) 65 ACA10 20 100% Solution to oil Precipitation at the Precipitation 0213-A Akomed R bottom MCT + cholesterol (40 mg/g) 66 ACA10 20 100% Solution to oil Precipitation in the whole Precipitation in the 0213-C Akomed R sample whole sample MCT + cholesterol (60 mg/g) 67 ACA10 20 100% Solution to oil Precipitation directly after Precipitation in the 0213-B Akomed R evaporation whole sample MCT + cholesterol (80 mg/g) 68 ACA10 25 50% Akoline Solution to oil Unchanged Unchanged A portion of 0301-1 MCM, 50% the sample Akomed R was placed in MCT + the cholesterol refrigerator: (50 mg/g) partial solidification after 1 day, but clear solution after melting at RT. After another 1 day in the fridge the sample started to precipitate Massive precipitation after 25 weeks 69 ACA10 25 50% Akoline Solution to oil Unchanged Unchanged after 25 A portion of 0301-2 MCM, 50% weeks the sample Akomed R was placed in MCT + the cholesterol refrigerator: (75 mg/g) partial solidification, but clear solution after melting at RT. The sample withstood repeated cycles during several weeks without precipitationI 70 ACA10 25 50% Akoline Solution to oil Very small amount of Precipitation A portion of 0301-3 MCM, 50% needle-shaped crystals the sample Akomed R after 1 day was placed in MCT + the cholesterol refrigerator: (100 mg/g) partial solidification and very slight precipitation after melting at RT 71 ACA10 30 50% Akoline Solution to oil Unchanged after 3 days, Precipitation A portion of 0301-4 MCM, 50% slight tendency to the sample Akomed R precipitation after 5 days was placed in MCT + the cholesterol refrigerator: (60 mg/g) partial solidification and slight precipitation after melting at RT 72 ACA10 30 50% Akoline Solution to oil Unchanged after 3 days, Precipitation A portion of 0301-5 MCM, 50% precipitation after 5 days the sample Akomed R was placed in MCT + the cholesterol refrigerator: (90 mg/g) partial solidification and substantial precipitation after melting at RT 73 ACA10 30 50% Akoline Solution to — — — 0301-6 MCM, 50% crystals Akomed R (precipitated MCT + during cholesterol evaporation; (120 mg/g) discarded) 74 ACA10 25 50% Akoline Solution to oil Unchanged Unchanged Batch size 100 g 0320 MCM, 50% Very slight Akomed R precipitation MCT + after 23 weeks cholesterol (75 mg/g) 75 ACA10 20 30% Akoline Solution to oil Unchanged Unchanged Batch size 100 g 0321 MCM, 70% Slight Akomed R precipitation MCT + after 23 weeks cholesterol (60 mg/g)

Example 76

The objective of the study was to investigate the comparative pharmacokinetics in plasma of a 3-beta-hydroxy-5-alpha-pregnan-20-one formulation comprising sesame oil and cholesterol following subcutaneous administration to New Zealand White rabbits. Two groups of three female rabbits each received single doses 1 mg/kg (formulation as in example 7) or 5 mg/kg (formulation as in example 10). Following subcutaneous injection into the dorsal neck region of the animals, blood samples were taken at 0.25, 0.5, 1, 2, 4, 6, 8, 12 and 24 hours post dose. Concentrations of 3-beta-hydroxy-5-alpha-pregnan-20-one in plasma were measured by a validated LC-MS/MS method. Data are presented in FIG. 1, and show mean plasma concentration (ng/mL) of 3-beta-hydroxy-5-alpha-pregnan-20-one for the two doses: 1 mg/kg (squares) and 5 mg/kg (circles).

Example 77

Suspensions of 3-beta-hydroxy-5-alpha-pregnan-20-one were prepared for investigation of solubility as follows: cholesterol was first dissolved at room temperature in sesame oil at 10 and 20 mg/ml, respectively. Suspensions of 3-beta-hydroxy-5-alpha-pregnan-20-one in sesame oil with different amounts of cholesterol were prepared on a magnetic stirrer at about 500 rpm using a conventional Teflon coated stir bar, at room temperature for several days, with occasional cycling to 2-8° C. At this time, the particles have become substantially smaller. Thereafter, samples of the respective suspensions were filtered through a 0.2 μm filter and analyzed with regard to concentration of 3-beta-hydroxy-5-alpha-pregnan-20-one. The results are presented in Table 3 and FIG. 2 where it can be seen that increasing the amounts of cholesterol increases the soluble fraction of 3-beta-hydroxy-5-alpha-pregnan-20-one. FIG. 2 shows data for a 3-beta-hydroxy-5-alpha-pregnan-20-one concentration of 10 mg/g. FIGS. 3a and 3b show microscopy pictures taken at 5× enlargement of suspensions with a 3-beta-hydroxy-5-alpha-pregnan-20-one concentration of 10 mg/g and a cholesterol:3-beta-hydroxy-5-alpha-pregnan-20-one ratio of 1:1 immediately upon mixing (3 a) and after several days of stirring (3 b).

TABLE 3 3-beta-hydroxy-5-alpha-pregnan-20-one The weight ratio concentration in filtrate (mg/ml) cholesterol to 3- Initial 3-beta- Initial 3-beta- beta-hydroxy-5- hydroxy-5-alpha- hydroxy-5-alpha- alpha-pregnan- pregnan-20-one pregnan-20-one 20-one concentration 10 mg/g concentration 40 mg/g 0:1 1   — 1:4 — 1.4 1:2 — 1.9 1:1 1.8 — 2:1 2.2 —

Example 78

Micronized 3-beta-hydroxy-5-alpha-pregnan-20-one (10 mg/g) with a mean particle size of 6 micrometer was suspended in sesame oil with cholesterol (20 mg/g) and stirred as in example 77. Photos were taken immediately upon suspension (FIG. 4a ) and after 19 hours of stirring (FIG. 4b ).

CONCLUSION

It has been shown that the presence of a sterol such as cholesterol improves the possibilities to formulate 3-beta-hydroxy-5-alpha-pregnan-20-one in a pharmaceutical composition comprising acylglycerols, either as an oily solution or an oily suspension. 

The invention claimed is:
 1. A pharmaceutical oil composition, consisting of: 3-beta-hydroxy-5-alpha-pregnan-20-one; cholesterol or an ester thereof; and a mixture of acylglycerols, wherein the mixture of acylglycerols is a medium-chain acylglycerol.
 2. The pharmaceutical oil composition according to claim 1 wherein the mixture of acylglycerols has a total combined percentage of (i) fatty acids with eight carbon atoms and (ii) fatty acids with ten carbon atoms of at least 95%.
 3. The pharmaceutical oil composition according to claim 1, wherein the 3-beta-hydroxy-5-alpha-pregnan-20-one is essentially dissolved.
 4. The pharmaceutical oil composition according to claim 1, wherein the 3-beta-hydroxy-5-alpha-pregnan-20-one is in the form of an oil suspension consisting of some of the 3-beta-hydroxy-5-alpha-pregnan-20-one in the form of suspended particles and some of the 3-beta-hydroxy-5-alpha-pregnan-20-one dissolved in the oil composition.
 5. The pharmaceutical oil composition according to claim 1, wherein the medium-chain acylglycerol consists of from about 50% to about 65% of monoacylglycerols, about 25% to about 35% of diacylglycerols, less than about 5% of triacylglycerols and less than about 2.5% of glycerol.
 6. A pharmaceutical oil composition for parenteral administration according to claim
 1. 7. A pharmaceutical oil composition for vaginal administration according to claim
 1. 8. A method of terminating steroid induced anesthesia, comprising: administering the pharmaceutical composition according to claim 1 to a subject in need thereof.
 9. The pharmaceutical oil composition according to claim 1, wherein said medium-chain acylglycerol is a mixture of acylglycerols wherein the total combined percentage of fatty acids with 8 carbon atoms and 10 carbon atoms is at least 95%.
 10. The pharmaceutical oil composition according to claim 1, wherein said medium-chain acylglycerol comprises at least about 95% triacylglycerols.
 11. The pharmaceutical oil composition according to claim 1, wherein said medium-chain acylglycerol is a mixture of acylglycerols wherein the total combined percentage of fatty acids with 8 carbon atoms and 10 carbon atoms is at least 95% and said medium-chain acylglycerol comprises at least about 95% triacylglycerols. 